The pistil of the saffron flower is composed of, from the top, a stigma, a style, and an ovary. The stigma has a bright red color and contains useful components including medicinal components, flavoring components and pigments.
The saffron stigmata containing the useful components have been conventionally harvested from the pistils of open saffron flowers. In general, a big saffron bulb weighing about 30g gives rise to only about 6 flowers, each having three-divided stigma. Thus, one can harvest only about 18 stigmata per bulb at the most. In order to collect, for example, 1 kg of stigmata, the required amount of bulbs would amount to about 500 kg. Therefore, the production of large quantities of saffron stigmata requires the cultivation of considerable acreage.
Moreover, natural cultivation is time consuming and subject to weather conditions. Further, saffron is extremely unsuited for repeated cultivation on the same ground. Hence, it is difficult to efficiently produce saffron pitilliary stigmata by cultivation. Thus, saffron stigmata produced under these circumstances, are very expensive.
It has been proposed to culture the organs of the saffron flower to produce a stigma-like tissue, for example, culture the female organ (i.e., pistil) of the saffron flower in the presence of cytokinins and/or orxines to produce a saffron stigma-like tissue (i.e., pistil like tissue) as disclosed in JP-A-62-275617 (the term "JP-A" as used herein means an "unexamined published Japanese patent application"); culture the female organ (i.e., stigma, pistile, ovary or ovule) or a petal of the saffron flower in the presence of cytokinins and orxines as disclosed in JP-A-63-258574. However, a satisfactory technique has not yet been established to obtain sufficient quantities of the saffron stigma-like tissue and the saffron pigment. Thus, there has been a great demand to develop a technique for effectively obtaining saffron useful components.